Method for observing high-altitude neutral air and device for observing high-altitude neutral air

ABSTRACT

Ion particles are discharged so as to be trapped with magnetic field lines of the earth, and collided with high-altitude neutral air to generate high velocity neutral particles through charge exchange. The high velocity neutral particles are trapped. In this case, the distance to the high-altitude neutral air from at least one of the discharging positions of the ion particles and the trapping positions of the high velocity neutral particles is determined on the period of time between the discharging timings of the ion particles and the trapping timings of the high velocity neutral particles. Moreover, the direction of the high-altitude neutral air is determined on the trapping direction of the high velocity neutral particles. In addition, the space position of the high-altitude neutral air is determined on the trapping direction of the high velocity neutral particles.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates to a method for observing high-altitudeneutral air and a device for observing high-altitude neutral air whichare usable in space operational business enterprise and space weatherforecast business enterprise.

[0003] 2. Description of the Related Art

[0004] As has gotten a lot of attention in the falling of the Mir spacestation at March, 2001, if a large-scaled space structure is plungedinto atmosphere and reached to earth, it is concerned that the spacestructure affects on our social life to some degree. In this point ofview, data concerning high-altitude neutral air are very importantbecause the orbit altitude of a space satellite may be decreased due tothe atmosphere drag in the high-altitude neutral air and the plungetiming of the space satellite into atmosphere can be predicted from thehigh-altitude neutral air data.

[0005] In a conventional observation for the high-altitude neutral air,an observing instrument is mounted on a space satellite, which isdisposed in the high-altitude neutral air. As a result, since theobserving instrument is positioned in a given area of the high-altitudeneutral air, the observation for the high-altitude neutral air iscarried out at every area where the observing instrument is positioned.

[0006] Since the observing area is contaminated by positioning the spacesatellite, with the conventional technique, the high-altitude neutralair can not be observed precisely. Moreover, with the conventionaltechnique, only the data concerning a given area of the high-altitudeneutral air by positioning the observing instrument in the given areacan be obtained, so the total data concerning the high-altitude neutralair can not be obtained simultaneously.

[0007] The data concerning the high-altitude neutral air can be obtainedfrom the Jacchia model (Standard Jacchia Reference Atmosphere 1977)which is a simulated and modeled distribution of high-altitude neutralair on the changes in altitude of many space satellites launched in thepast. Since the predictive accuracy of the Jacchia model is poor,however, it can not be employed in a technical field requiring promptresponse and accuracy such as the prediction in atmosphere plunge of aspace satellite and the like.

SUMMERY OF THE INVENTION

[0008] It is an object of the present invention, in this point of view,to observe the high-altitude neutral air widely and precisely.

[0009] In order to achieve the above-mentioned objects, this inventionrelates to a method for observing high-altitude neutral air, comprisingthe steps of:

[0010] discharging ion particles so as to be trapped with magnetic fieldlines of the earth,

[0011] colliding the ion particles with high-altitude neutral air togenerate high velocity neutral particles through charge exchange, and

[0012] trapping the high velocity neutral particles to determine thedistance to the high-altitude neutral air from at least one of thedischarging positions of the ion particles and the trapping positions ofthe high velocity neutral particles on the period of time between thedischarging timings of the ion particles and the trapping timings of thehigh velocity neutral particles, to determine the direction of thehigh-altitude neutral air on the trapping direction of the high velocityneutral particles, and to determine the space position of thehigh-altitude neutral air.

[0013] In the present invention, for example, a given ion source isdisposed on the orbit of the earth, and then, ion particles aredischarged from the ion source so as to be trapped by the magnetic fieldlines of the earth. When the ion particles are collided with thehigh-altitude neutral air, high velocity neutral particles are generatedthrough the charge exchange with the ion particles in the high-altitudeneutral air. The neutral particles travel inertially without thedisturbance of the magnetic field lines of the earth, and trapped with agiven neutral particle analyzer disposed on the orbit of the earth.

[0014] The discharging velocities of the ion particles can bepredetermined, and the velocities of the neutral particles can bemeasured with the neutral particle analyzer. Moreover, the relativeposition between the ion source and the neutral particle analyzer can bepredetermined, and the discharging angles of the ion particles from theion source and the observing angle of the neutral particle analyzer canbe predetermined. Therefore, if the periods of time between thedischarging timings of the ion particles and the trapping timings of theneutral particles are measured, at least one of the distances betweenthe high-altitude neutral air and the ion source and between thehigh-altitude neutral air and the neutral particle analyzer can bedetermined.

[0015] Moreover, since the neutral particles can be trapped with theneutral particle analyzer, the direction of the high-altitude neutralair can be determined from the trapping directions of the neutralparticles.

[0016] In addition, in the present invention, since the distance for thehigh-altitude neutral air and the direction of the high-altitude neutralair are measured as mentioned above, the space position of thehigh-altitude neutral air can be determined therefrom.

[0017] Herein, the wording “high-altitude neutral air” means anatmosphere within an altitude range of about 100 km-1000 km.

[0018] Also, the wording “charge exchange” means a reaction where an ionparticle “A” is collided with an ion particle “B”, causing the chargetransfer of the ion particle “A” to the ion particle “B” and thus,generating a high velocity neutral particle “A” and a high velocityneutral particle “B” (A*+B→A+B*).

[0019] In the present invention, since the high velocity neutralparticles can be generated from the charge exchange with the ionparticles in the high-altitude neutral air, if the trapping frequency ofthe neutral particles is measured with the neutral particle analyzer,the particle density of the high-altitude neutral density can bedetermined.

[0020] If the ion particles are made of the same particles as theneutral particles, the energies of the ion particles and the energies ofthe neutral particles can be conserved before and after the collisionbetween the ion particles and the neutral particles. Therefore, thekinetic energies of the neutral particles are equal to the kineticenergies of the ion particles. In contrast, if the ion particles aremade of different particles from the neutral particles, the kineticenergies of the neutral particles are increased and decreased on thedifferences in ionization voltage between the ion particles and theneutral particles before and after the collision therebetween

[0021] Since the sorts of the ion particles are known, if the increasingand decreasing in kinetic energy of the ion particles are measured, thesorts of particles in the high-altitude neutral air can be determinedthrough the collision, and thus, the composition of the high-altitudeneutral air can be determined.

[0022] It is desired that the ion particles are made of particles whichrarely exist on the high and low orbits of the earth. In this case, theion particles can be recognized clearly against other particles in thespace. Concretely, the ion particles may be made of krypton particles orxenon particles.

[0023] The ion particles may be discharged in pulse or modulation. Inthis case, the discharging timings of the ion particles and the trappingtimings of the high velocity neutral particles can be recognizedclearly, and the distance for the high-altitude neutral air can bemeasured easily and precisely.

[0024] In this way, according to the present invention, the spaceposition, the density and the composition of the high-altitude neutralair can be determined precisely. If the discharging angles of the ionparticles from the ion source and the observing angle of the neutralparticle analyzer are controlled appropriately, the density and thecomposition of the high-altitude neutral air can be widely determined ina short period of time.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] For better understanding of the present invention, reference ismade to the attached drawings, wherein

[0026]FIG. 1 is an explanatory view relating to a method for observinghigh-altitude neutral air according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] This invention will be described in detail with reference to theaccompanying drawings.

[0028]FIG. 1 is an explanatory view relating to a method for observinghigh-altitude neutral air according to the present invention. In FIG. 1,an ion cluster source is disposed as an ion source on the orbit abovethe equator of the earth, and a neutral particle analyzer is disposed inthe rear side of the ion cluster source. Ion particles are dischargedfrom the ion cluster source, and trapped with the magnetic field linesgenerated from the axis of the earth. In this case, the ion particlesare rotated along the magnetic field lines, which is defined as “Larmormotion”, and moved north and south. If a given condition is satisfied,the mirror confining mechanism is generated, so that the ion particlesare moved repeatedly north and south.

[0029] In this case, the ion particles are collided with inner particlesin the high-altitude neutral air (not shown) at the black points in FIG.1, causing the charge transfer of the ion particles to the innerparticles and thus, generating neutral particles in the directionsdesignated by the arrows. The neutral particles travel inertially attheir respective high velocities without the disturbance of the magneticfield lines, and trapped and detected with the neutral particleanalyzer.

[0030] The discharging velocities of the ion particles can bepredetermined, and the velocities of the neutral particles can bemeasured with the neutral particle analyzer. On the other hand, therelative position between the ion cluster source and the neutralparticle analyzer can be predetermined. In addition, the dischargingangles of the ion particles from the ion cluster source can bepredetermined and the observing angle of the neutral particle analyzercan be predetermined. Therefore, if the periods of time between thedischarging timings of the ion particles and the trapping timings of theneutral particles are measured, at least one of the distances betweenthe high-altitude neutral air and the ion cluster source and between thehigh-altitude neutral air and the neutral particle analyzer can bedetermined.

[0031] The direction of the high-altitude neutral air can be determinedfrom the trapping directions of the neutral particles with the neutralparticle analyzer.

[0032] As mentioned above, it is desired that the ion particles are madeof particles which rarely exist on the orbit of the earth such askrypton particles or xenon particles in order to be distinguished fromother particles in nature. In order to enhance the easiness andprecision of the measurement of the distance for the high-altitudeneutral air, the ion particles may be discharged in pulse or modulation.

[0033] If the trapping frequency of the neutral particles are measuredwith the neutral particle analyzer, the particle density of thehigh-altitude neutral air can be determined because the high velocityneutral particles can be generated through the charge exchange with theion particles in the high-altitude neutral air. If the changes inkinetic energy of the neutral particles are measured, the composition ofthe high-altitude neutral air can be determined because the sorts of theion particles are known and thus, the changes in kinetic energy of theneutral particles depend on the sorts of particles in the high-altitudeneutral air.

[0034] In this embodiment, since it is not required that the ion clustersource and the neutral particle analyzer are disposed directly in thehigh-altitude neutral air, the space position, the density and thecomposition of the high-altitude neutral air can be determined preciselywithout the contamination of the ion cluster source, the neutralparticle analyzer and the like. Moreover, if the discharging angles ofthe ion particles from the ion cluster source and the observing angle ofthe neutral particle analyzer are controlled appropriately, the densityand the composition of the high-altitude neutral air can be determinedwidely in a short period of time.

[0035] It may be that the ion cluster source and the neutral particleanalyzer can be mounted on a space satellite which is disposed on theorbit of the earth. In this case, if the position of the space satelliteis adjusted, the ion cluster source and the neutral particle analyzercan be disposed as illustrated in FIG. 1 to observe the high-altitudeneutral air. The ion cluster source and the neutral particle analyzercan be mounted on the same space satellite or respective different spacesatellites. In the latter case, since the degree of freedom indisposition of the ion cluster source and the neutral particle analyzercan be increased, the high-altitude neutral air can be observed andmeasured wider.

[0036] Although the present invention was described in detail withreference to the above examples, this invention is not limited to theabove disclosure and every kind of variation and modification may bemade without departing from the scope of the present invention.

[0037] As mentioned above, according to the present invention, since itis not required that the ion source and the neutral particle analyzerare disposed directly in the high-altitude neutral air, the spaceposition, the density and the composition of the high-altitude neutralair can be determined precisely. Moreover, when the discharging anglesof the ion particles from the ion source and the observing angle of theneutral particle analyzer are controlled appropriately, the density andthe composition of the high-altitude neutral air can be determinedwidely in a short period of time.

1. A method for observing high-altitude neutral air, comprising thesteps of: discharging ion particles so as to be trapped with magneticfield lines of the earth, colliding said ion particles withhigh-altitude neutral air to generate high velocity neutral particlesthrough charge exchange, and trapping said high velocity neutralparticles to determine the distance to said high-altitude neutral airfrom at least one of the discharging positions of said ion particles andthe trapping positions of said high velocity neutral particles on theperiod of time between the discharging timings of said ion particles andthe trapping timings of said high velocity neutral particles, todetermine the direction of said high-altitude neutral air on thetrapping direction of said high velocity neutral particles, and todetermine the space position of said high-altitude neutral air.
 2. Theobserving method as defined in claim 1, wherein the density of saidhigh-altitude neutral air is determined on the trapping frequency ofsaid high velocity neutral particles.
 3. The observing method as definedin claim 1, wherein the composition of said high-altitude neutral air isdetermined on the changes in kinetic energy of said high velocityneutral particles for said ion particles.
 4. The observing method asdefined in claim 1, wherein said ion particles are made of kryptonparticles and/or xenon particles.
 5. The observing method as defined inclaim 1, wherein said ion particles are discharged in pulse.
 6. Theobserving method as defined in claim 1, wherein said ion particles aredischarged in modulation.
 7. A device for observing high-altitudeneutral air, comprising: an ion source disposed on an orbit of theearth, and a neutral particle analyzer disposed on an orbit of theearth.
 8. The observing device as defined in claim 7, wherein said ionsource discharges ion particles so as to be trapped with magnetic fieldlines of the earth.
 9. The observing device as defined in claim 8,wherein said ion particles are made of krypton particles and/or xenonparticles.
 10. The observing device as defined in claim 8, wherein saidion particles are discharged in pulse.
 11. The observing device asdefined in claim 8, wherein said ion particles are discharged inmodulation.
 12. The observing device as defined in claim 8, wherein saidneutral particle analyzer traps high velocity neutral particles whichare generated from said ion particles through the collision of said ionparticles with high-altitude neutral air and the charge exchange withsaid ion particles.
 13. The observing device as defined in claim 7,wherein said ion source and said neutral particle analyzer are mountedon the same space satellite.
 14. The observing device as defined inclaim 7, wherein said ion source and said neutral particle analyzer aremounted on respective difference space satellites.